Subject: Re: [PATCH v2 2/4] rust: nvmem: Add an abstraction for nvmem providers

From: Link Mauve <[email-masked]>
Date: Thu, 5 Feb 2026 13:48:32 +0100

On Wed, Feb 04, 2026 at 04:22:16PM +0100, Danilo Krummrich wrote:
> On Wed Feb 4, 2026 at 5:04 AM CET, Link Mauve wrote:
> > +impl Device {
> > +    /// Register a managed nvmem provider on the given device.
> > +    pub fn nvmem_register<T>(&self, mut config: NvmemConfig<T>, priv_: &T::Priv)
> > +    where
> > +        T: NvmemProvider + Default,
> > +    {
> > +        // FIXME: The last cast to mut indicates some unsoundness here.
> > +        config.inner.priv_ = core::ptr::from_ref(priv_).cast::<c_void>().cast_mut();
> > +        config.inner.dev = self.as_raw();
> > +        config.inner.reg_read = Some(NvmemConfig::<T>::reg_read);
> > +        config.inner.reg_write = Some(NvmemConfig::<T>::reg_write);
> > +        // SAFETY: Both self and config can’t be null here, and should have the correct type.
> > +        unsafe { bindings::devm_nvmem_register(self.as_raw(), &config.inner) };
> > +    }
> > +}
> 
> This should not be a method on the generic device type. Typically we use a
> Registration struct for this, i.e. this would become
> nvmem::Registration::register().

Should I also switch to the nvmem_register()/nvmem_unregister() API
instead of the devm_nvmem_register() API, so that the unregister can
happen in the Drop impl instead of being managed by the kernel?

-- 
Link Mauve